1. Field of the Invention
The invention is related to an optical device, and in particular to a backlight module.
2. Description of Related Art
As the electronic industry prospers, flat panel displays have gradually replaced cathode ray tube displays to become the current mainstream product. Among the flat panel displays, liquid crystal displays (LCD) are more technologically matured and more popular. However, since a liquid display panel of an LCD does not emit light, a backlight module is disposed beneath the liquid display panel as a light source, so that display functions are achieved.
In a backlight module, a light emitting strip including a plurality of light emitting diodes (LED) is assembled on a back plate, and heat generated by the light emitting diodes is dissipated by the back plate when the light emitting diodes emit light. Hence, parts of the back plate closer to the LEDs have higher temperature, whereas parts of the back plate farther from the LEDs have lower temperature, so that bending and distortion of the back plate is caused by an uneven temperature distribution. Therefore, angles at which light from the LEDs enters the light guide plate deviate. Taiwan patent no. M286937, M351369, and Taiwan patent application publication no. 200628918 disclose technologies relevant to light source devices.